Jessop's estimate for the construction of the line was £38,167 10s 0d. With the exception of
Laigh Milton Viaduct at Gatehead, and soft ground at Shewalton Moss, the engineering works on the line were light. The line was engineered "as a plateway at a time when other Scottish lines were using the edge rail". The choice of the older technology may be due to the employment of
William Jessop as engineer. He had built the
Surrey Iron Railway, also a plateway. The wrought iron rails were L-shaped, and the upstand guided the wagons; the wagon wheels did not have flanges, which enabled them to be easily moved around terminal areas where there was hard standing, and to and from locations further from the railway. The plates were three feet long, with a four-inch width and a three-inch upstand (920 mm long by 100 mm by 76 mm). Highet says, "These plates or rails were joined with a square joint and were nailed to the foundation stones through small square holes formed half-way in each end of the rail." In January 1812, the
Scots Magazine described the line, then not quite finished; it would be double track with frequent crossovers: The road is to be double, or two distinct roads of four feet in width each, and laid four feet distance from each other, with frequent communications from the one road to the other, so as not only to admit of carriages going both ways, but to allow one carriage to pass another when both are travelling in one direction. It would have a gentle gradient of about 1 in 660 (0.15%) falling towards Troon: The total rise of the ground, from the Troon Harbour to Kilmarnock, is 80 or 84 feet, which is equally divided over the whole course of the road, so as to form it into an inclined plane, having a declivity of nearly eight feet, every mile. The track is described in more detail: The iron rails are 3 feet in length, and 40 lbs in weight each. Their horizontal base, on which the carriage wheels run, is 4 inches in breadth, and the ledge or parapet, rising perpendicular in the inner side of the rail, is also about 4 inches in height, raised in the centre, and declining at both ends of each rail, to add to its strength. [The rails] are not laid on sleepers of wood; but on solid blocks of stone, from 9 to 12 inches in thickness, and generally more than a foot square (in base and surface). The ground, on which these blocks are laid, is beat solid, and the stones are also beat down, after being laid, so as to give them all the solidity possible. The iron rails are bedded level on the blocks, and a hole about an inch and a quarter diameter, in the centre of each, six inches deep, is filled with a plug of oak; and a square niche being formed in the centre, at both ends of each of the rails, about half an inch above, and something narrower below, and when the ends of two of these rails are put together, the niches in each of the two rails, form one hole about an inch in length, and more than half an inch in breadth, contracting a little below; and these being placed over the plug of wood, in the centre of the block of stone, a nail is fixed into it, the head of which exactly fills up the holes in the ends of the two rails, and the holes and heads of the nails, being broader above than below, they keep the rails solid and firm on their beds. The space of four feet between the rails is filled with road metal for the horse, to near the top of the ledges of the rails, and the outside to the sole of the rails. The majority of the rails for constructing the line were made by the Glenbuck Iron Company; by 1813 they had been paid £13,345 for about 72,000 rails; this was about a third of the entire engineering cost of building the line. ==Opening and operation==